The invention relates to a screw-in multi-way seat valve according to the preamble of claim 1.
Such a screw-in multi-way seat valve is known from the technical brochure D7921 “Screw-in Seat Valve Type BVE”, March 2008-00, of the company HAWE Hydraulik SE, Streitfeldstrasse 25, 81673 Munich, DE. The screw-in housing of the known screw-in multi-way seat valve is unitary with the solenoid tube of the actuating solenoid (page 4 of the technical brochure D7921) and ends with an exterior thread section. A first sleeve is pressed from below into the screw-in housing in sealed fashion. A first valve seat is formed at the first sleeve. The valve member is inserted through the first sleeve and the screw-in housing from below before, due to the larger outer diameter of the seat surface of the valve member, a second sleeve is pressed from below into firm abutment on the first sleeve. A second valve seat is provided in the second sleeve. Both seat surfaces of the valve member alternatingly co-operate with both valve seats when the valve member executes a stroke of about 0.8 mm to 1.0 mm and when an armature of the actuating solenoid pulls counter to the force of a closing spring. In the threaded-in condition of the screw-in multi-way seat valve the second sleeve is pressed into abutment against a shoulder of a stepped bore. A pole core of the actuating solenoid is axially fixed at a stop via the first sleeve. Several structural separation regions exist is axial direction between the armature of the actuating solenoid and the second valve seat such that, due to unavoidable manufacturing tolerances, the axial distance between the first and second valve seats and the distances of the first and second valve seats from the armature may undesirably fluctuate within a production series. A subsequent adjustment to compensate for such fluctuations is impossible without dismantling several components and without expensive re-machining of components. However, compensating for such fluctuations would be important in order to achieve an optimum and constant relationship between the course of the solenoid force and the stroke of the valve member within a production series.
Further prior art is contained in: U.S. Pat. No. 4,542,879 A, DE 41 18 190 A, GB 233 850 A, GB 220 219 A and U.S. Pat. No. 4,834,337 A.